Water closet tank



FIG. 1 is a pespective view taken from the top, front and left side of a water closet tank embodying our new design;

FIG. 2 is a right side elevational view thereof, the left side being the mirror image of the right side;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a rear elevational view thereof; and,

FIG. 6 is a bottom plan view thereof.

The fragmentary broken line representations of mounting and access holes in FIGS. 1 and 6 are for the purpose of illustration only and form no part of the claimed design. 

The ornamental design for a water closet tank, as shown and described. 